While the volatility of the steel market is one of the reasons that users consider and then choose Dura-Bar to replace steel, the main reason for switching is to take advantage of the†of the materialís machinability and lower end-cost of the component. Three case studies demonstrate the successes that companies have experienced using Dura-Bar ductile iron. These examples -- two for the same application -- show specific benefits that users have discovered.They also illustrate the specific types of steel that make ideal candidates for evaluating alternatives.
Chain Roller Replacement
Two companies that manufacture chain rollers switched from steel to Dura-Bar but made the decision based on different factors.
One company making standard and heat-treated rollers wanted to reduce part cost to be more competitive. To replace 1117 and 1045 steel, it chose two grades of Dura-Bar. In both cases, faster machining was just the initial cost savings. They chose Dura-Bar 65-45-12, the fastest machining grade, for parts that required heat-treating. This allowed them to machine the parts the fastest and then heat-treat for improved wear. Also since 65-45-12 does not have to be carburized they saved even more. Using Dura-Bar 80-55-06 for non-heat-treated parts, provided similar properties to 1045 steel with easier machining. With both materials, the company achieved machine time savings to improve its competitive position.
The second company had a process bottleneck in the area of heat treating. To keep up with the 1117 cold drawn parts coming from its turning centers, an in-house heat treatment facility had to work overtime. Since Dura-Bar does not require carburizing prior to heat treatment, its use sped up the heat treat cycle and reduced the time required to produce the part. The companyís testing of Dura-Bar ductile 65-45-12 for internal crush, wear and notch tests showed performance equal to, and in some cases better than, 1117 steel. By using as-cast Dura-Bar, instead of cold finished steel, the material costs were almost equal. However, the annual cost savings from machining and heat-treating just one part was estimated at over $200,000!
Compressor Valves Victory
A manufacturer of engineered valves made products with a wide selection of materials, ranging from ductile castings to 17-7PH stainless steel. In this case, Dura-Barís excellent machinability and specifically its drillability reduced the total time required to make the parts and provided a significant cost reduction. With Dura-Barís ability to machine at higher speeds, the manufacturer increased drilling speeds, produced more parts per hour and even had increased tool life.
Besides the cost savings in production, the application capability of Dura-Bar provided additional advantages. Valves operating in severe compression and sour gas environments had dictated using higher cost materials like stainless steel. The consistent microstructure of Dura-Bar and its ability to handle severe compressive strengths, allowed the customer to use it in a wider range of applications, in some cases, replacing stainless steel. Because Dura-Bar oxidizes but does not decompose as quickly as steel, it can last longer in certain applications.
More Ideal Applications
In general, switching primarily from carbon steel grades such as those mentioned has proven benefits in production and service. Other ideal applications include products that have a large amount of machining or require the wear properties of the ductile iron, such as vane rotors and chain rollers. For these and similar applications, investigating the ductile iron option could provide a compelling reason to change for cost, performance or reliability and in some cases Ė all three.